pgReQ is a LISTEN/NOTIFY-based request exchange mechanism for clients connecting to a PostgreSQL server.
The name pgReQ is short for postgres Request Queue.
pgReQ is a solution for developers who need to implement inter-process communication between applications connecting to the same postgres database.
pgReQ maintains three queues:
Incoming requests the client has accepted and has to process/respond to (until they expire)
Requests the client has made to other clients and are awaiting response (until they expire)
Responses to requests the client has made to other clients (and they came back with a reply)
pgReQ does not control or enforce program flow: It only maintains the queues. The rest is up to your application.
For integrating pgReQ to your application you can either use an event-based model or poll the queues at your own convenience.
pgReQ can be used to implement both client-server and peer-to-peer communication.
There is no extensive documentation on the classes. Study the demo application.
It shows all you need to know for using the two pgReQ classes.
Hope you find it useful.